JPS633697A - Control device for generator for vehicle - Google Patents

Abstract

PURPOSE:To prevent engine stall, by controlling the generating condition of a generator based on the number of revolutions of an engine and intercylindrical pressure of cylinders. CONSTITUTION:A regulator 18 controls battery voltage Vatt so as to be equal to the reference voltage Vref. On the other hand, a control unit 21 is fitted to a crank shaft 12A of an engine 12 and detects the number of revolutions of the engine based on the crank angle signal CR from a crank angle sensor 26. In accordance with this number of revolutions of the engine the reference voltage Vref is set up, while the reference voltage Vref is changed so as to be equal to the battery voltage Vatt when it is judged from the intercylindrical pressure signal P of the engine 12 that the engine is in danger of stalling.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a vehicle power generation number control device that controls power generation operation according to the state of an engine.

(Prior Art) As a conventional control device of this type, there is one shown in FIG. 4, for example (see Japanese Patent Laid-Open No. 59-56900).

In FIG. 4, the rotational speed signal of the engine 1 is input to the rotational speed detection circuit 2, and the rotational speed detection circuit 2 generates an output voltage nO proportional to the rotational speed. This output voltage Vno
is input to the comparator 5 of the regulator 4 via the delay circuit 3, and the comparator 5 compares the delayed voltage Vn with the divided voltage VS of the battery 6. Divided voltage VS is delay circuit 3
When the voltage is lower than the voltage Vn set in , the transistor 7 is turned on and current flows through the field winding 9 of the generator 8
The battery 6 is charged by causing the generator 8 to generate electricity. When the divided voltage VS of the battery 6 rises and becomes higher than the voltage Vn of the delay circuit 3, the transistor 7 is turned off to cut off the field winding current. In this way, the divided voltage Vs of the battery 6 is controlled to be equal to the adjusted voltage vn determined by the delay circuit 3.

Further, the adjustment voltage Vn has an upper limit value Vn2 and a lower limit value Vn1.
The upper limit value Vn2 is set to a value that does not significantly shorten the life of the vehicle's headlamps, etc., and the lower limit value ■n1 is set to a value that does not over-discharge the battery 6 (see Figure 5). B), see>.Also, the output voltage Vno of the rotation speed detection circuit 2 is set constant when the engine rotation speed N exceeds a predetermined value N3, and the upper limit value Vn2 is set constant, and the matching with the engine output characteristic [raw] is performed. I try to maintain it in good condition (Figure 5 (A>, (B), (
b) ~ (see 2)).

(Problem to be solved by this invention) However,
In such a conventional vehicle generator control device,
The state of the engine was determined by representing the engine speed, and the power generation status was controlled according to this speed, and power generation was stopped when the speed exceeded a certain level.
When a large electrical load (e.g. blower motor, headlamp, air conditioner, etc.) is applied when the engine speed is low, such as when idling, the battery voltage drops and current flows through the field winding, causing the generator to stop generating power. Become. As a result, the load of the generator on the engine becomes excessive, and
There was a problem that the engine stalled.

(Means for Solving the Problems) The present invention was made in view of the above problems, and was made for the purpose of controlling the generator in accordance with the state of the engine. Its basic conceptual diagram is shown in FIG. That is, the present invention includes a power generation control means 18 that controls the power generation state of the on-vehicle generator 11, a rotation speed detection means 26 that detects the rotation speed of the on-board engine, and an in-cylinder pressure detection means that detects the in-cylinder pressure of the on-board engine. 27 and
The control means 21 is provided for controlling the operation of the power generation limiting means 18 based on the output of the rotation speed detecting means 26 and the output of the cylinder pressure detecting means 27.

(Function) In this invention having such a configuration, the power generation state of the generator is controlled based on the engine speed and the cylinder pressure, so the power generation state can be changed according to the engine state. At the same time, when an engine stall is expected to occur, power generation is produced, so the load of the generator on the engine can be reduced, and the occurrence of an engine stall can be prevented.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIGS. 2 and 3 are diagrams showing one embodiment of the present invention.

First, to explain the configuration, in FIG. 2, reference numeral 11 is a generator driven by an engine 12.
is a stator winding 13 that is connected in a Y-connection to induce three-phase alternating current, and a rectifier diode 1 that rectifies the generated three-phase alternating current.
4, and a field winding 16 and a diode 17 that generate magnetic flux by the current from the battery 15. The power generation state of the generator 11 is controlled by a regulator (power generation control means) 18. That is, the regulator 1B has a comparator 19 and an output transistor 20, and the comparator 19 receives the battery voltage V from the battery 15.
att and the reference voltage V from the control unit 21
ref are respectively input. Therefore, Va
When tt<Vref, the output transistor 20 is turned on and current flows through the field winding 16, causing the generator 11 to generate electricity and charging the battery 15. When vatt≧Vref, the output transistor 20 is turned on and the field Cut off the winding current. Thus, the battery voltage vatt
is controlled to be equal to the reference voltage V ref.

The control unit 21 includes a CPU 22, an A/D converter 23, a D/A converter 24, a drive circuit 25, etc., and the control unit 21 includes a crank angle sensor ( The crank angle signal CR from the rotation speed detection means) 26 is inputted, and the cylinder pressure of the engine 12 detected by the cylinder pressure sensor (cylinder pressure detection means) 27 is converted into a pressure signal P by the pressure conversion circuit 2B and inputted. ing.

The control unit 21 detects the engine speed based on the crank angle signal CR, sets the reference voltage ref according to this engine speed, and also sets the in-cylinder pressure signal P.
When it is determined that there is a risk of engine stalling based on the above, the reference voltage Vref is changed to be equal to the battery voltage vatt (yrer=■att>.

Next, the effect will be explained.

The comparator 19 receives the battery voltage Va from batch 1) 15.
tt and a reference voltage Vrer corresponding to the engine speed from the control unit 21 are respectively input, and when Vrer > Vatt, the output transistor 20
turns on and current flows through the field winding 16. Therefore, the power generation method 11 performs power generation, and the battery 15
is charged. When Vref≦v att, the generator 11 stops generating electricity.

Here, the control unit 21 controls the cylinder pressure sensor 27.
When it is determined that there is a risk of engine stalling in the engine 12 based on the cylinder pressure signal P from
Vref = Vatt) change. Therefore, in this case, the power generation action of the power generation method 11 is stopped, and the load on the engine 12 is reduced.

Next, a method for determining the risk of engine stalling will be explained based on the flowchart of the control program shown in FIG. In addition, in the figure, 81 to 310 indicate each step, and this control program is executed, for example, in synchronization with the engine speed.

First, the cylinder pressure signal P is sent to the control unit 21 using Sl.
and crank angle signal CR, and in S2, both signals P and CR are converted into digital signals by the A/D converter 23, and then these digital signals are stored in the memory. In S3, the integral value K of the cylinder pressure is calculated between the predetermined crank angles according to the following formula 1, K=fPdV...1 Next, in S4, the integrated value laS for all cylinders is calculated according to the following formula 2 Calculate according to

S= (1/n>ΣK...2 Next, in S5, this integrated value S is compared with the stall limit direct H3, and when S<H3, it is determined that there is a risk of engine stalling, and S6 If S≧IS, it is determined that there is no risk of engine stalling and the process proceeds to S7.The stall limit value H3 is a value obtained experimentally in advance according to the engine speed. Stored in memory as a table map.

In S6, there is a risk of engine stalling, so the CPU
21 outputs the engine stall signal E to the drive circuit 25. Therefore, a reference voltage V ref equal to the battery voltage vatt is input to the comparator 19 via the drive circuit 26 . Therefore, the output transistor 20 is turned off and no current flows through the field winding 16, so that the power generation action of the power generation method 11 is stopped, and charging of the battery 15 is also stopped.

Next, the engine stall timer is started in S7, but if the engine stall timer is pressed in S8, for example, if 1 second has elapsed, power generation will be stopped as is, and if the engine stall timer is more than 1 second The signal is turned off, and the engine stall timer is stopped while being reset at 310. By providing hysteresis, the power generation method 11 is prevented from being turned on and off frequently.

As described above, in this embodiment, by comparing the integrated value S of the cylinder pressure with the stall limit value T as, an unstable state of combustion that may cause engine stall is determined, and the danger of engine stall is determined. When the engine stops running, the load of the generator 11 on the engine 12 is reduced and the engine speed is increased. As a result, it is possible to prevent engine stall from occurring when the electrical load suddenly increases when the engine speed is low, such as during idling. Further, since the reference voltage V ref is set in proportion to the engine speed, the power generation state can be changed depending on the engine state, and as a result, the engine output can be used effectively.

(Effects of the Invention) As explained above, since the power generation state of the generator is controlled based on the engine speed and the cylinder pressure,
It is possible to effectively utilize the output of the engine, and by determining the combustion state of the engine, it is possible to prevent the occurrence of engine stall.

[Brief explanation of drawings]

Fig. 1 is a basic conceptual diagram of the present invention, Fig. 2 is a block diagram showing an embodiment of the invention, Fig. 3 is a flowchart showing its control program, Fig. 4 is an electric circuit diagram showing a conventional example, and Fig. 4 is a block diagram showing an embodiment of the invention. Figures 5A and 5B are characteristic diagrams showing the control characteristics. 11: Power generation valve 18 Recipulator (power generation control means) 21: Control unit (control means) 26 2 Rotation speed sensor (rotation speed, detection means) 27: Cylinder pressure sensor (cylinder pressure detection means) Fig. 1 Fig. 3 Fig. 4 ! ! ! ! ↓ Figure 5

Claims (1)

[Claims] A power generation control means for controlling the power generation state of the on-board generator, a rotation speed detection means for detecting the rotation speed of the on-board engine, an in-cylinder pressure detection means for detecting the cylinder pressure of the on-board engine, and an output of the rotation speed detection means. A control device for a vehicle generator, comprising: control means for controlling the operation of the power generation control means based on the output of the cylinder pressure detection means.